1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.util; 18 19 import java.util.ArrayList; 20 21 import android.os.SystemClock; 22 23 /** 24 * A utility class to help log timings splits throughout a method call. 25 * Typical usage is: 26 * 27 * <pre> 28 * TimingLogger timings = new TimingLogger(TAG, "methodA"); 29 * // ... do some work A ... 30 * timings.addSplit("work A"); 31 * // ... do some work B ... 32 * timings.addSplit("work B"); 33 * // ... do some work C ... 34 * timings.addSplit("work C"); 35 * timings.dumpToLog(); 36 * </pre> 37 * 38 * <p>The dumpToLog call would add the following to the log:</p> 39 * 40 * <pre> 41 * D/TAG ( 3459): methodA: begin 42 * D/TAG ( 3459): methodA: 9 ms, work A 43 * D/TAG ( 3459): methodA: 1 ms, work B 44 * D/TAG ( 3459): methodA: 6 ms, work C 45 * D/TAG ( 3459): methodA: end, 16 ms 46 * </pre> 47 * 48 * @deprecated Use {@link android.os.Trace}, or 49 * <a href="https://developer.android.com/studio/profile/benchmark">Android Studio</a>. In 50 * general, milliseconds is the wrong granularity for method-level tracing. Rounding errors 51 * can overemphasize cheap operations, or underemphasize repeated operations. This timing 52 * system also does not take CPU scheduling or frequency into account. 53 */ 54 @Deprecated 55 public class TimingLogger { 56 57 /** 58 * The Log tag to use for checking Log.isLoggable and for 59 * logging the timings. 60 */ 61 private String mTag; 62 63 /** A label to be included in every log. */ 64 private String mLabel; 65 66 /** Used to track whether Log.isLoggable was enabled at reset time. */ 67 private boolean mDisabled; 68 69 /** Stores the time of each split. */ 70 ArrayList<Long> mSplits; 71 72 /** Stores the labels for each split. */ 73 ArrayList<String> mSplitLabels; 74 75 /** 76 * Create and initialize a TimingLogger object that will log using 77 * the specific tag. If the Log.isLoggable is not enabled to at 78 * least the Log.VERBOSE level for that tag at creation time then 79 * the addSplit and dumpToLog call will do nothing. 80 * @param tag the log tag to use while logging the timings 81 * @param label a string to be displayed with each log 82 */ TimingLogger(String tag, String label)83 public TimingLogger(String tag, String label) { 84 reset(tag, label); 85 } 86 87 /** 88 * Clear and initialize a TimingLogger object that will log using 89 * the specific tag. If the Log.isLoggable is not enabled to at 90 * least the Log.VERBOSE level for that tag at creation time then 91 * the addSplit and dumpToLog call will do nothing. 92 * @param tag the log tag to use while logging the timings 93 * @param label a string to be displayed with each log 94 */ reset(String tag, String label)95 public void reset(String tag, String label) { 96 mTag = tag; 97 mLabel = label; 98 reset(); 99 } 100 101 /** 102 * Clear and initialize a TimingLogger object that will log using 103 * the tag and label that was specified previously, either via 104 * the constructor or a call to reset(tag, label). If the 105 * Log.isLoggable is not enabled to at least the Log.VERBOSE 106 * level for that tag at creation time then the addSplit and 107 * dumpToLog call will do nothing. 108 */ reset()109 public void reset() { 110 mDisabled = !Log.isLoggable(mTag, Log.VERBOSE); 111 if (mDisabled) return; 112 if (mSplits == null) { 113 mSplits = new ArrayList<Long>(); 114 mSplitLabels = new ArrayList<String>(); 115 } else { 116 mSplits.clear(); 117 mSplitLabels.clear(); 118 } 119 addSplit(null); 120 } 121 122 /** 123 * Add a split for the current time, labeled with splitLabel. If 124 * Log.isLoggable was not enabled to at least the Log.VERBOSE for 125 * the specified tag at construction or reset() time then this 126 * call does nothing. 127 * @param splitLabel a label to associate with this split. 128 */ addSplit(String splitLabel)129 public void addSplit(String splitLabel) { 130 if (mDisabled) return; 131 long now = SystemClock.elapsedRealtime(); 132 mSplits.add(now); 133 mSplitLabels.add(splitLabel); 134 } 135 136 /** 137 * Dumps the timings to the log using Log.d(). If Log.isLoggable was 138 * not enabled to at least the Log.VERBOSE for the specified tag at 139 * construction or reset() time then this call does nothing. 140 */ dumpToLog()141 public void dumpToLog() { 142 if (mDisabled) return; 143 Log.d(mTag, mLabel + ": begin"); 144 final long first = mSplits.get(0); 145 long now = first; 146 for (int i = 1; i < mSplits.size(); i++) { 147 now = mSplits.get(i); 148 final String splitLabel = mSplitLabels.get(i); 149 final long prev = mSplits.get(i - 1); 150 151 Log.d(mTag, mLabel + ": " + (now - prev) + " ms, " + splitLabel); 152 } 153 Log.d(mTag, mLabel + ": end, " + (now - first) + " ms"); 154 } 155 } 156